Until recently, removable storage media were predominantly magnetic diskettes such as 51/4 or 31/2 inch removable diskette. In order to control unauthorized copying of software, various software based solutions such as specially formatted diskettes, or hardware based solutions such as dongles have been in use. These solutions, generally, barred the possibility of copying an original licensed user application program (stored in the form of one or more files) to different, unauthorized, sites in which they are used freely without the owner's consent. The proposed solutions posed some difficulties in terms of assuring that the protected modules that are incorporated into the user application do not interfere with the normal operation of the protected application, and therefore a significant portion of the computer industry did not adopt them as a standard solution and preferred to rely on legal different approaches such as copyright enforcement. In the past few years the removable medium which serves for storage of user application programs has migrated to CD-ROM which not only is characterized by a larger storage volume as compared to the ancestor magnetic storage medium, but provides an inherent copy protection feature. Thus, a magnetic storage medium such as a diskette can be easily copied by using a conventional operating system utility (e.g. "diskcopy" in the DOS operating system). Conversely, in order to copy a CD-ROM, special equipment is required which, until recently, carried a very high price tag, thus hindering the possibility of circulated copying of the original CD-ROMs. Software developers coudl therefore rely on the fact that in order to exploit their software, an original CD-ROM must be purchased and the likelihood of copying the original CD-ROM is negligible. This situation has recently been changed with the introduction of relatively cheaper CD-ROM copying devices which now facilitate unauthorized copying of CD-ROMs, thereby causing significant financial damages to the software developers. The recent advent of so called DVD (standing for Digital Video Disk) has further aggravated the problem since the latter enables not only to read data but also to write data thereon. Thus, by utilizing conventional DVD driver, files from an original CD-ROM may be copied to a blank DVD carrier and used without the consent of the software developer.
Accordingly, there arises a need in the art to incorporate in an original CLV carrier, means which will hinder the possibility of illegally copying and using part or all of the data stored in the original CLV carriers. CLV carrier, as is well known in the art, stands for Constant Linear Velocity which is the underlying technology shared by CD-ROM carrier, DVD carrier and others.